Give the control records their layouts, a person's policy and its one derivation, and the engine's own packages key, so the assigner, the indexer and the nodes keep them without the controller (issue 1953 L5-S2, S3, S4)

go/buscompose/engine.go

@@ -3,6 +3,7 @@ package buscompose
 import (
 	"git.novox.be/novox/mesh-sdk/go/asks"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"git.novox.be/novox/mesh-sdk/go/delivery"
 )
 
 // The node seat node-engine (novox/hq ADR 0563 §1): every node's engine holds it on its own bus account, and no module
@@ -22,6 +23,16 @@ const (
 // EngineActsBucket is that state's bucket.
 var EngineActsBucket = BucketName(EngineModule, EngineActsState)
 
+// EnginePackagesBucket is the engine's state of its node's declared packages (novox/hq ADR 0565 clause 6): one key, the
+// node's name, written by that node's engine alone.
+var EnginePackagesBucket = BucketName(EngineModule, delivery.EnginePackagesState)
+
+// EnginePackagesGrants is what a node's engine publishes to keep its node's key of the packages bucket: the key alone,
+// and its read.
+func EnginePackagesGrants(node string) []string {
+	return append([]string{"$KV." + EnginePackagesBucket + "." + node}, readGrants(EnginePackagesBucket, node)...)
+}
+
 // engineGrants is what a node's engine is granted to hold its node seat and to ask the operator (ADR 0563 §1, §3): it
 // answers its own node's verbs (the caller-named subjects are added beside them with every principal's), says the
 // seat's events about its node, answers discovery for the seat, asks who answers what (the login shell's execute, ADR
@@ -41,5 +52,9 @@ func engineGrants(p Principal) (pub, sub []string) {
 	if own, err := NodeKeysGrants(EngineActsBucket, p.Node); err == nil {
 		pub = append(pub, own...)
 	}
+	// And its node's declared packages, its own key alone (ADR 0565 clause 6).
+	if safeSubject.MatchString(p.Node) {
+		pub = append(pub, EnginePackagesGrants(p.Node)...)
+	}
 	return append(pub, tp...), append(sub, ts...)
 }